. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 6. Macrophotographs of a: the Proteus larva (27 mm length); b, the larva (27 mm length) with a grafted Euproctus eye; c, the Euproctus larva (19 mm in length) ; d, the Euproctus larva (19 mm length) with a grafted Proteus eye. Conservation of the primitive lumen of the lens, permanence of lytic processes, and the possibility of nucleolar segregation in the cells of the cornea all demon- strate that the involution of the epiblastic derivatives of the eye corresponds to the persistence of a cellular metabolic disturbanc
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 6. Macrophotographs of a: the Proteus larva (27 mm length); b, the larva (27 mm length) with a grafted Euproctus eye; c, the Euproctus larva (19 mm in length) ; d, the Euproctus larva (19 mm length) with a grafted Proteus eye. Conservation of the primitive lumen of the lens, permanence of lytic processes, and the possibility of nucleolar segregation in the cells of the cornea all demon- strate that the involution of the epiblastic derivatives of the eye corresponds to the persistence of a cellular metabolic disturbance (normal but transitory during the ocular development of other vertebrates). Biometrics can be used to confirm the cytological findings. It is clear that the curves (Fig. 4) represent the growth of the eye and the lens and satisfy respectively the functions: bxa and bx" xe~"'x. The growth pattern of the lens is of the same type as the one for the eye and needs only be differentiated by the complementary term e''1*, where yx can be considered as the expression of the involutive phenomenon superimposed upon the normal growth of the lens. In summary, the slowness of the processes of growth and of involution (along with the modifications which accompany them) suggests that there is in the lens a state of relative equilibrium between the processes of synthesis and degeneration. Photosensitive retina. The photosensitive retina is composed of a pigmented epithelium which appears poorly developed (Nguyen Legros and Durand, 1974). The visual cells of Proteus (Fig. 5a) appear to be degenerated if compared to those of other Urodela. One can find, however, the elements essential to a photo- receptor : the cell body, the inner segment with mitochondria, and a basal centriole sending ciliary fibrils through a peduncle which supports the outer segment. The. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - c
Size: 1331px × 1876px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
